Tunable Surface Selenization on MoO2 -Based Carbon Substrate for Notably Enhanced Sodium-Ion Storage Properties.

Transition metal chalcogenides with high theoretical capacity are promising conversion-type anode materials for sodium ion batteries (SIBs), but often suffer from unsatisfied cycling stability (hundreds of cycles) caused by structural collapse and agglomerate. Herein, a rational strategy of tunable surface selenization on highly crystalline MoO2 -based carbon substrate is designed, where the sheet-like MoSe2 can be coated on the surface of bundle-like N-doped carbon/granular MoO2 substrate, realizing partial transformation from MoO2 to MoSe2 , and creating b-NC/g-MoO2 @s-MoSe2 -10 with robust hierarchical MoO2 @MoSe2 heterostructures and strong chemical couplings (MoC and MoN). Such well-designed architecture can provide signally improved reaction kinetics and reinforced structural integrity for fast and stable sodium-ion storage, as confirmed by the ex situ results and kinetic analyses as well as the density functional theory calculations. As expected, the b-NC/g-MoO2 @s-MoSe2 -10 delivers splendid rate capability and ultralong cycling stability (254.2 mAh g-1 reversible capacity at 5.0 A g-1 after 6000 cycles with ≈89.0% capacity retention). Therefore, the tunable surface strategy can provide new insights for designing and constructing heterostructures of transition metal chalcogenides toward high-performance SIBs.

Association between body mass index and myopia in the United States population in the National Health and Nutrition Examination Surveys 1999 to 2008: a cross-sectional study.

BACKGROUND: This study investigated the association between body mass index (BMI) and myopia in the United States. METHODS: This cross-sectional study included 8,000 participants from the 1999 to 2008 National Health and Nutrition Examination Survey (NHANES). BMI was classified into four groups: < 18.5, 18.5 - 24.9, 25-29.9, and > 29.9. Three diagnostic thresholds were used for myopia A\B\C: spherical equivalent ≤ -0.5\-0.75\-1 diopters in the right eye. Multivariate logistic regression analysis and smooth curve fitting were performed to evaluate the association between BMI and myopia. RESULTS: The incidence of myopia was 39.4%. BMI was correlated with myopia, with each 1 kg/m2 increase in BMI associated with a 1% increase in the risk of myopia (OR, 1.01; 95% CI 1.01 1.02; p < 0.05). In myopia B, after adjusting for confounding factors, compared with the reference group (BMI 18.5-24.9), participants with a BMI of 25-29.9 and greater than 29.9 had a 14% and 25% increased risk of myopia, respectively (OR 1.14; 95% CI 1.01 1.29; p = 0.037, OR 1.25; 95% CI 1.08 1.44; p = 0.003), which was similar to the results for myopic A (OR, 1.15; 95% CI 1.02 1.3; p = 0.027, OR 1.19; 95% CI 1.03 1.37; p = 0.018) and myopia C (OR 1.15; 95% CI 1.01 1.31; p = 0.035, OR 1.18; 95% CI 1.01 1.37; p = 0.032). Moreover, there was a linear relationship between myopia and BMI (p for nonlinearity = 0.767). CONCLUSIONS: Myopia using all three diagnostic thresholds was positively associated with higher BMI. This suggests a potential association between myopia and higher BMI in the American population, warranting further investigations.

Porous N-doped carbon with confined Fe-doped CoP grown on CNTs for superefficient oxygen evolution electrocatalysis.

Herein, Fe-doped CoP nanoparticles (Fe-CoP NPs) encapsulated in porous N-doped carbon (PNC)/carbon nanotubes (CNTs) have been successfully synthesized. The Fe doping and confined structures resulted in enhanced charge transfer and improved active sites for intermediates adsorption. The obtained Fe-CoP@PNC/CNTs materials exhibited superefficient OER performance.

Encapsulating N-Doped Carbon Nanorod Bundles/MoO2 Nanoparticles via Surface Growth of Ultrathin MoS2 Nanosheets for Ultrafast and Ultralong Cycling Sodium Storage.

Conversion-type anode materials possess high theoretical capacity for sodium-ion batteries (SIBs), owing to multi-electron transmission (2-6 electrons). Mo-based chalcogenides are a class of great promise, high-capacity host materials, but their development still undergoes serious volume changes and low transport kinetics during the cycling process. Here, MoO2 nanoparticles anchored on N-doped carbon nanorod bundles (N-CNRBs/MoO2) are synthesized by a facile self-polymerized route and a following annealing. After hydrothermal sulfuration, N-CNRBs/MoO2 composites are encapsulated by surface growth of ultrathin MoS2 nanosheets, acquiring hierarchical N-CNRBs/MoO2@MoS2 composites. Serving as the SIB anode, the N-CNRBs/MoO2@MoS2 electrode exhibits significantly improved sodium-ion storage properties. The reversible capacity is up to 554.4 mA h g-1 at 0.05 A g-1 and maintains 249.3 mA h g-1 even at 10.0 A g-1. During 5000 cycles, no obvious capacity decay is observed and the reversible capacities retain 334.8 mA h g-1 at 3.0 A g-1 and 301.4 mA h g-1 at 5.0 A g-1. These properties could be ascribed to the vertical encapsulation of MoS2 nanosheets on high-crystalline N-CNRBs/MoO2 substrates. The hierarchical architecture and unique heterostructure between MoO2 and MoS2 synergistically facilitate sodium-ion diffusion, relieve volume changes, and boost pseudocapacitive charge storage of N-CNRBs/MoO2@MoS2 electrode. Therefore, the rational growth of nanosheets on complex substrates shows promising potential to construct anode materials for high-performance batteries.

Novel agaric-derived olive-like yolk-shell structured MnO@C composites for superior lithium storage.

Unique hierarchical olive-like yolk-shell structured MnO@C composites were customized via an ingenious and effective biomass strategy. This structure, with internal void spaces, accommodated the volume variations of MnO, and the N-doped porous carbon shells ensured the rapid transport of Li+/electron species. When used as anodes for LIBs, ultrastable rate and cycling performances were obtained.

Enhanced Cyclability and High-Rate Capability of LiNi0.88Co0.095Mn0.025O2 Cathodes by Homogeneous Al3+ Doping.

To suppress capacity fading of nickel-rich materials for lithium-ion batteries, a homogeneous Al3+ doping strategy is realized through tailoring the Al3+ diffusion path from the bulk surface to interior. Specifically, the layered LiNi0.88Co0.095Mn0.025O2 cathode with the radial arrangement of primary grains is successfully synthesized through optimization design of precursors. The Al3+ follows the radially oriented primary grains into the bulk by introduction of nano-Al2O3 during the sintering process, realizing the homogeneous Al3+ distribution in the whole material. Particularly, a series of nano-Al2O3-modified LiNi0.88Co0.095Mn0.025O2 are investigated. With the 2% molar weight of Al3+ doping, the capacity retention ratio of the cathode is tremendously improved from 52.26 to 91.57% at 1 C rate after 150 cycles. Even at a heavy current density of 5 (&10) C for the LiNi0.88Co0.095Mn0.025O2-Al2% cathode, a high reversible capacity of 172.3 (&165.7) mA h g-1 can be acquired, which amount to the 84.46 (&81.25) % capacity retention at 0.2 C. Moreover, voltage deterioration is significantly suppressed by homogeneous Al3+ doping from the results of median voltage and dQ/dV curves. Therefore, homogeneous Al3+ doping benefited from the radial arrangement of primary grains provides an effective and practical way to prolong lifespan, as well as improves rate performance and voltage stability of nickel-rich ternary materials.